Final answer:
An AFFF extinguisher is intended for use on class B fires. Class B fires involve flammable liquids such as gasoline, oil, and grease.
Step-by-step explanation:
An AFFF (Aqueous Film Forming Foam) extinguisher is intended for use on class B fires. Class B fires involve flammable liquids such as gasoline, oil, and grease. AFFF is a type of foam that creates a film on the surface of the liquid, smothering the fire and preventing re-ignition.